The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Whipstrut on 11.02. 2019 17:55

Title: Engine case bolt lengths
Post by: Whipstrut on 11.02. 2019 17:55
I'm beginning the engine machine work, and I'm wondering if someone out there could provide me with the case bolt lengths required on my A10 SA. These would be 67-350, 29-4101,  and 67-352. Because of shipping costs from England, I'd like to source locally. Any other info is greatly appreciated too.
Title: Re: Engine case bolt lengths
Post by: Swarfcut on 11.02. 2019 18:37
Whipstrut.... There is nothing special about these items. Unless you are absolutely determined to use genuine parts, either used or new old stock, they can be produced locally. Luckily for you, searching the first item in the Literature Section above will bring up a useful table of part numbers and specification.    Joolstacho.. Nut and Bolt.

    The first post is by the highly regarded Muskrat, and  following the link to stainless should give you the information you need.  The alternative is readily available so called "Pattern Parts", of varying quality, and a choice of material, mild steel or stainless. If you make your own, any readily available fine thread would do for the fine end. BSA used the BS CEI (Cycle Thread). As their heritage was in bicycle manufacture,  this thread was also most suited to the motorcycle manufacturing requirement.  BSW is the Whitworth thread, the coarse thread used where the studs go into the softer aluminium of the crankcases. So here you have to stick with Whitworth.

Title: Re: Engine case bolt lengths
Post by: Whipstrut on 11.02. 2019 19:44
Thanks loads, that's exactly the info. I was needing, although my eyeballs were burn't to raisins with the super small print on my phone.
I don't post as often as I thought I would, but reading the posts of others is priceless.